Japanese Patent Application Laid-Open No. 2005-277481 discloses a wireless LAN system including a wireless LAN terminal which communicates with an access point via a wireless LAN and also communicates with a terminal apparatus via a wired LAN. FIG. 12 shows a typical block diagram of such a wireless LAN system. Here, it will be shown as an example that a terminal apparatus 104-1 transmits a BC or MC (BroadCast or MultiCast) packet. The BC/MC packet transmitted by the terminal apparatus 104-1 is transmitted to a wireless LAN terminal 100 and a terminal apparatus 104-2. The wireless LAN terminal 100 transmits the BC/MC packet received from the terminal apparatus 104-1 to an access point 106 via the wireless LAN. In this case, the access point 106 transmits back the BC/MC packet to all the wireless LAN terminals including the wireless LAN terminal 100. The wireless LAN terminal 100 outputs the BC/MC packet to a wired LAN port 102. That is, the terminal apparatus 104-1 connected with the wired LAN port 102 receives the BC/MC packet which the terminal apparatus 104-1 has transmitted. Meanwhile, the terminal apparatus 104-2 connected with the wired LAN port 102 receives again the BC/MC packet already received. Due to such returning and double transmission, traffic in the wired LAN increases.
Meanwhile, a learning bridge function disclosed in Japanese Patent Application Laid-Open No. 1998-285200 or the like is well known. The learning bridge function is specified in IEEE802.1d standard or the like. When a packet is relayed among a plurality of LAN interfaces, the learning bridge function is carried out. When the learning bridge function is installed in the wireless LAN terminal 100 shown in FIG. 12, the wireless LAN terminal 100 learns a MAC address of the terminal apparatus connected with the wired LAN port 102 on the basis of a packet received via the wired LAN port 102. Then, the wireless LAN terminal 100 discards a BC/MC packet transmitted by the terminal apparatus connected with the wired LAN port 102 among the BC/MC packets received from the access point 106 based on a result of the learning. Because of the discarding a packet, the terminal apparatus connected with the wired LAN port 102 does not receive the returned packet and the double transmission packets. Accordingly, increase of the traffic in the wired LAN is suppressed.